JPS6253038A - Duplicated system for data transmission equipment - Google Patents

Abstract

PURPOSE:To improve the reliability of a data transmission by providing two transmission lines in parallel lines in parallel each composing of a line driver and a receiver and reception equipment and selecting other path if one path is failed. CONSTITUTION:Two transmission paths A, B composing of respectively line divers 5, 6 transmission lines 9, 10, receivers 7, 8 and reception equipments 3, 4 are provided in parallel. Then the 1st failure detection circuit 12 supervises always the output state of transmitters A, B and when a fault is detected, a switching signal is outputted to change over a switch SW1. When both the transmitters A, B are normal, either of them has a priority. Further, the 2nd fault detection circuit 14 supervises always the state of the reception equipment 4, 5 and when a fault is detected, a changeover switch SW2 is selected to either normal of the positions A, B.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention is directed to a duplex system in a device that transmits data.

[Technical drawbacks of the invention and its problems]

Conventionally, in this type of system, two series of transmission apparatuses, each consisting of a transmitter, a driver, a transmission path, a receiver, and a receiver, are connected in parallel, and when one series fails, switching to the other series is performed.

For this reason, for example, two transmission lines between one transmitter and the other
When a problem occurs in a particular location, it is not possible to respond appropriately, resulting in a situation where data transmission is interrupted for a long time until the problem is recovered.

(Object of the Invention) Here, the present invention overcomes the difficulties of the conventional example, and solves the problem of component destruction in a digital data serial transmission device.
To provide a redundant system for data transmission equipment that reduces the risk of becoming unable to transmit due to failure of i-line, etc.
That purpose.

(Summary of the Invention) In order to achieve the above object, the present invention provides a transmission device that serially transmits digital data, and a transmitting device that performs P/S conversion at both sending and receiving ends of two parallel transmission paths. Line driver, line receiver, S/
Using two receiving devices each that perform P conversion, two transmission paths consisting of a line driver, line receiver, and receiving device are connected in parallel, and either transmitting device A or B connected to the two transmission paths is connected. A switch SW1 selects the received data, a switch SW2 selects either the A side or the B side of the transmission path, and the switch SW1 receives signals tj indicating the status of each transmitter from the transmitters △ and B. and a second failure detection circuit that receives signals representing the states of the respective receivers R1'f from the receivers A and B and controls the switch SW2 in a mil manner.

This is a duplex system of data transmission equipment characterized by the following.

[Embodiments of the invention]

FIG. 1 shows a block diagram showing a circuit configuration in an embodiment of the present invention.

1.2 is a transmitting device Δ, B that performs P/S conversion (converts a parallel signal to a serial signal) and transmits digital data serially; 3.4 performs S/P conversion from a serial signal to a parallel signal. The receiving devices 'eIA, B, 5.6 are line drivers A, B, 7.8 that send data to the transmission path.
are line receivers A and B that accept data from the transmission path.
, 9.10 is transmission path A for transmitting data, 8.11 is 1
, 2 transmitting devices HA, B, and a switch (SWI) that switches which transmitting device is connected to the transmission line based on a command from the first failure detection switching circuit 12.
, 13 is a switch (SW2) that connects or switches one of the receiving devices to the internal device 15 in response to a command from the second failure detection switching circuit 14 based on the information from the receiving devices A and B in 3.4. .

-f % That is, the present invention includes a line driver 5.6, a transmission line 9.10, a receiver 7.8, and a receiving device! Two transmission paths, △ and B, consisting of 13°4 are provided in parallel.

Transmitting device 1.2 and A, using 82 units, e.g. relay, 3
State batshu? [Active high H voltage and low Lf
A switch 11 (SWI) consisting of a buffer with three states: fl pressure and non-active (high impedance).
], 2 transmission RffiA, B, the flow of data transmission can be controlled.

The data then passes through transmission lines A and B of 5.6 drivers A and B → 9 degrees and 10 of 3.8 and receivers A and B of 7.8.
4 to receiving devices A and B.

Here, the switch 13 (SW2) for selecting data from the receiving devices aA and B of 3.4 is set mi:J. The same means as the switch SW1 on the transmitting side is applied to this switch SW2.

Next, the first failure detection switching circuit 12 is connected to the transmitting device ff1A.
, B are constantly checked, and when an abnormality is detected, an Akashi signal is output and the switch (SWl) 11 is turned off. However, if the transmitting devices 1 and 2 are normal, they are free to give priority to connecting to the A side.

Similarly, the second fault detection circuit 14 constantly monitors the state of the receiver, and when an abnormality is detected, it switches the switch (S
W2) Switch 13 to either A or B, whichever is normal.

Therefore, the circuit configuration shown in FIG. 2 can be considered as an example of the first and second failure detection switching circuits 12 and 14.

140 continuously generates pulses with a constant period or 0
141 and 142 are counters that count the number of inputs to the CLKE child by J1, and are reset by the data pulse from the CLKGa child. The terminal is the output terminal when the counter overflows. 14
3 is an AND (logical product) circuit, and since the output phase is inverted, it is a NAND circuit. The 0 mark attached to each of the CLR terminal of the counter and the input terminal at the lower end of the NAND circuit 143 is a symbol for inverting the input phase.

For example, when data is being transmitted on transmission line A and everything is normal, the counter CLK and Otsuk are input continuously.
The data input to the CLK terminal is not accepted due to phase inversion, and the data input to the Q terminal is not accepted. Since the overflow output continues from 1 to 1, the NAND 143 does not issue a switching signal to the switch 13.

However, when the transmission line A fails, the overflow of the counter 141 is no longer output, and the overflow output of the counter 142 is output and inverted at the input side of the NAND 143, so the NAND circuit 143 switches the switching signal to the switch (S
W2) 13, and the switch Ia piece is connected to the receiving device Ff14.
It falls to the side, and data is transmitted to the internal device 15 via transmission path B.

〔Effect of the invention〕

Thus, according to the present invention, even if there is a failure in the transmitter circuit △ and the transmission line B, or there is a problem in two different lines such as the LLI line, sufficient transmission is possible by appropriately switching the switches SW1 and SW2. Therefore, data transmission l
It has many potential contributions to this field because it increases the efficiency of data transmission in redundant systems, and in particular significantly improves the reliability of data transmission.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the circuit configuration of an embodiment of the present invention, and FIG. 2 is a route diagram of the failure detection circuit. 1.2... Transmitter A, B, 3.4... Receiver Wi
A. B, 5.6... Line driver A, B, 7.8...
Line drivers A, B, 9.10...transmission lines A, B,
DESCRIPTION OF SYMBOLS 11... Switch (SWI), 12... First failure detection switching circuit, 13... Switch (SW2), 14...
...Second failure detection circuit, 15...Internal equipment.

Claims (1)

[Scope of Claims] 1. A device for serially transmitting digital data, which includes a transmitting device that converts a parallel signal to a serial signal, a line driver that sends the serial signal to a transmission path, and a signal from the transmitting side to the receiving side. A transmission path for transmitting a signal, a line receiver for receiving a signal from the transmission path, and a receiving device for converting the received serial signal into a parallel signal are installed. →Means for connecting two transmission paths consisting of receiving devices in parallel, a first switch for selecting one or the other of the transmitting devices connected to the two transmission paths, and a means for connecting received data to the transmission path. a second switch that selects either one or the other; a first failure detection circuit that receives signals indicating respective transmission states from the two transmitters and controls switching of the first switch; 1. A duplex system for data transmission equipment, comprising: a second fault detection circuit that receives signals representing respective reception states from the reception equipment and controls switching of a second switch.